Choose the correct statements from the following.

(A) The collection of all possible combinations of goods and services that can be produced from a given amount of resources and a given stock of technological knowledge is called the production possibility frontier.

(B) Slope of production possibility frontier is called marginal opportunity cost.

(C) In positive economic analysis, we study how the different mechanisms function.

(D) Scarcity of resources gives rise to the problem of choice.

Statement (A) describes the Production Possibility Set. The Production Possibility Frontier refers specifically to the boundary or the maximum limit of that set. In strict economic terms, the collection of all possible combinations (including inefficient ones) is the set, while the frontier represents only the efficient ones.

Statement (B) is correct. The slope of the production possibility frontier is represented by:

$MRT = \frac{\Delta Y}{\Delta X}$

This ratio represents the marginal opportunity cost, which is the amount of one good sacrificed to produce an additional unit of another.

Statement (C) is correct. Positive economic analysis focuses on factual statements and cause-and-effect relationships. It explains how different economic mechanisms actually function without involving value judgments.

Statement (D) is correct. Scarcity is the root of all economic problems. Because resources are limited and wants are unlimited, society must choose which goods to produce and which to forgo.

Given that statement (A) is technically an inaccurate definition of the frontier, the most precise selection among the options provided is (B), (C), and (D) only.